Biomedical subjects

Lei Yang

Publications and source records attributed to Lei Yang.

96 records · Page 6Linked to original sources

PubMed2002

Isolation of acetylcholinesterase from apoptotic human lung fibroblast cells by antibody affinity chromatography.

Acetylcholinesterase (AChE; EC3.1.1.7) is well known for its role in the hydrolysis of acetylcholine at cholinergic synapses to terminate neurotransmission. In addition to its synaptic presence, AChE has been found to be in non-cholinergic cells such as hematopoietic and osteogenic cells. We have recently reported that AChE is expressed in various cells undergoing apoptosis. To characterize AChE in apoptotic cells and to investigate the role of AChE expression in apoptosis, we devised a method to purify AChE expressed in apoptotic human lung fibroblast cell line HLF. The isolation of this enzyme is mainly based on inhibitor ligand affinity chromatography using immobilized tacrine. However, this method is only effective in isolating active AChE. Here we employed antibody-based chromatography and found that both active and inactive AChE were present in apoptotic HLF cells. Active AChE was predominantly observed in the nuclei of apoptotic cells, while inactive AChE was mainly present in the cytoplasm. Therefore, our method provides an opportunity to investigate further the role of AChE, especially inactive AChE, in apoptosis.

Acetylcholinesterase↗

PubMed2002

[Protection effect of nerve implantation after peripheral nerve injury to rats].

OBJECTIVE: To investigate the protection effect of nerve implantation to the neurons after sciatic nerve injury to adult rats. METHODS: Thirty male Sprague-Dawley rats weighing 180 - 220 g (8 - 9 weeks of age) were randomly divided into four groups. Group A consisted of normal rats without operation. In group B, the sciatic nerve of rats was transected, with the proximal stump of the sciatic nerve ligated to inhibit nerve regeneration. In group C, a sciatic nerve crushed model was set up. In group D, a sciatic nerve implantation model was established. The rats were sacrificed on postoperative days 7, 14 and 28 respectively. The L(4)-L(6) segments of the spinal cord were harvested. TUNEL technique was used to detect apoptotic motor neurons. HE and Toluidine Blue staining was used for counting motor neurons. RESULTS: The apoptotic neurons detected on the 28th postoperative day were significantly fewer in the implantation group than in the other groups (P < 0.05). The number of motor neurons was significantly higher in the implantation group than in other two control groups (P < 0.05). CONCLUSIONS: Nerve implantation exerts protective effect on neurons after nerve injury.

Animals↗

PubMed2002

[Cloning expression of a novel human protein-disulfide isomerase like cDNA].

Using the large scale sequencing, a novel human cDNA of 1,645 bp was screened from the cDNA library of human fetal brain. The cDNA contains an ORF encoding a 296-aa protein with a calculated molecular weight of 34.0 KD. Compared with that of current sequence databases, the putative protein was found to have 36% homology with protein-disulfide isomerase (PDI). So this cDNA was named PDI like (PDI-L) gene. Multiple tissue Northern blot analysis shows that PDI-L cDNA is expressed in heart, brain, liver, kidneys and so on. The ORF fragment of PDI-L cDNA was inserted into reconstructed pBV220 expression vehicle and its predicted expressive protein was obtained.

Amino Acid Sequence↗

PubMed2001

Expression of cyclin D1 in small cell lymphoma and its clinical implications.

OBJECTIVE: To observe the expression of cyclin D1 and explore its clinical significance in small cell lymphoma. METHODS: Immunohistochemical method was used to detect the expression of CD20, CD45RO and cyclin D1 in 31 formalin- fixed and paraffin-embedded tissue samples of human small cell lymphomas. RESULTS: Twenty-eight cases were categorized into B cell lymphoma and 3 into T cell lymphoma. Only 5 cases of B cell lymphoma had cyclin D1 expression (17.86%) that did not significantly differ between nodal and extranodal lymphomas (P>0.05), indicating the presence of mantle cell lymphoma. CONCLUSION: The overexpression of cyclin D1 is a highly characteristic and specific indicator that discriminates mantle cell lymphoma from other small cell lymphomas, and this protein may offer critial guidance for therapeutic protocol and prognostic estimation.

Journal Article↗

PubMedDate not supplied

Ureteral intussusception due to a polyp.

Intussusception of the ureter is a rare complication of some ureteral diseases. A 49-year-old man was found to have a ureteral intussusception in the middle part of the right ureter accompanied by a polyp below the invaginated segment of the ureter. Surgery confirmed the diagnostic imaging findings. Here, we present a case of ureteral intussusception associated with a fibroepithelial polyp and discuss the radiological characteristics.

Diagnosis, Differential↗

PubMedDate not supplied

Studying the explanatory capacity of artificial neural networks for understanding environmental chemical quantitative structure-activity relationship models.

Although artificial neural networks (ANNs) have been shown to exhibit superior predictive power in the study of quantitative structure-activity relationships (QSARs), they have also been labeled a "black box" because they provide little explanatory insight into the relative influence of the independent variables in the predictive process so that little information on how and why compounds work can be obtained. Here, we have turned our interests to their explanatory capacities; therefore, a method was proposed for assessing the relative importance of variables indicating molecular structure, on the basis of axon connection weights and partial derivatives of the ANN output with respect to its input, which can identify variables that significantly contribute to network predictions, and providing a variable selection method for ANNs. We show that, by extending this approach to ANNs, the "black box" mechanics of ANNs can be greatly illuminated, thereby making it very useful in understanding environmental chemical QSAR models.

Algorithms↗